Selective automatic traffic regulating system



Sept. 24, 1940. P. l. Hmm Y 2,215,351

SELECTIVE AUTOMATIC TRAFFIC BEGULATING SYSTEM Filed 00?.. 4, 1935 4Sheet-sheet l idf mis

l Remy :zz

NVENTOR TTORNEYS SELECTIVE AUTOMATIC TRAFFIC REGULATING SYSTEM 3f P5055TRIAN A 89 /7 505 az lNvEN-ron Q2/fm' /mf pt. 24, 1940., p. p, HQRNI2,215,851

SELEGTIVE AUTOMATIC TRAFFIC REGULATING SYSTEM lFiled 001'.. 4, 1933 41Sheets-Sheet 3 AA?? Si. @Ene-C70@ f0.0 ya

PED STE/41V ETECTO/E @ELA V HNVENTOR ATTO R N EYS P. P. HURNII Sept. Z4,1940.

SELECTIVE AUTOMATIC TRAFFIC REGULATING SYSTEM Filed 00T.. 4. 1933 4Sheets-Sheet 4 INVENTOR ATTORNEYS atented Sept. 24, 1940 UNITED STATESPATENT OFFICE SELECTIVE AUTOMATIC TRAFFIC REGULAT- IN G SYSTEM 8 Claims.

This invention relates to automatic traiic regulating systems and hasparticular reference to a system which is selectively operable inaccordance with and in response to the volume and nature of the traiiicpassing the street intersection at which the system is located.

Various forms oi automatic traffic control systems have been devisedheretofore and include the familiar prexed timer system in which theright of way is alternately transferred from one intersecting street toanother; the so-called fully actuated system in which all of the streetsforming the intersection are provided with devices responsive to traillcapproaching the intersection for appropriating control of the signals soas to permit it to negotiate the intersection, examples of which areillustrated in United States Patents No. 1,538,952, issued May 26, 1925,to Ram, and No. 1,551,541, issued September 1, i925, to Collins; and thesemi-actuated or normal go system in which traftlc on a main highway orboulevard retains the right of way until trailic seeking to cross themain highway initiates a signal circuit, whereby the right of way istemporarily transferred to the cross street and is then restored to themain highway after a clearing period by a timing mechanism involvingeither a commutator or equivalent devices responsive to the passage ofcross trame from the signal zone, examples of which are disclosed inBritish Patent No. 138,792, to Badger, dated i919, and in United StatesReissue Patents No. 16,666, to Kennedy, dated September 15, 1925, andNo. 17,602, to Nelson, dated February i8, i930.

Each of these systems has certain advantages and disadvantages dependingupon several factors, among which are the nature and volume oi thetrailic negotiating the intersection, the nature of adjacent traiccontrol systems which may contribute to retarding or congesting trafiicinstead of dispatching it, variation in the volume and nature of traflicduring different times of the day, or at different seasons of the year,and the like. For example, the pre-xed timer type of trailc controlsystem has a distinct advantage if the nature and volume of the traic issubstantially uniform on all streets forming the intersectionbut if thisis not the case the system periodically halts trallc on the main highwayor boulevard or a heavily traveled street where there is no crosstrailic `to warrant the delay, so that congestion instead of dispatch ofthe traflic results.

The fully actuated type of tramo control system has distinct advantagesfor use at intersections where the trame is variable on several of thestreets forming the intersection, so that none of the streets couldproperly be considered to be a main highway or boulevard. and yet eachstreet passes such a considerable amount of trafnc at certain times ofthe day or other periods that it is warranted in maintaining the rightof way for as long a time as is necessary to dispatch the trafficnegotiating that street. However, this system has the disadvantage thatit is relatively expensive to install in intersections where the trafficis substantially uniform on all the streets, because in that event thesystem is working most of the time, where the less expensive and simplerpre-fixed timer system would be of greater advantage. Also. where one ofthe streets of the intersection passes more traffic than another, suchas a highway or boulevard, it is more appropriate to maintain the rightof way on the highway or boulevard so as to dispatch the heavier trainorather than cause the main highway or boulevard trame to initiate asignal cycle each time after crosstraveling trafc completed a signalcycle permitting it to negotiate the main highway or boulevard.

IThe semi-actuated or normal go trahie control system is of distinctadvantage at intersections comprising a relatively lightly-traveledcross street and a main highway or boulevard where the tramo isrelatively heavy or dense as compared to the cross traino, since, withthis system, heavier trallc on the main highway or boulevard retains theright of way with a normal go signal at all times, so that it isdispatched, unless and until cross traiic seeking to enter or cross themain highway or boulevard initiates the signal cycle by means responsiveto its presence, to permit it to cross the highway or boulevard, thesignal cycle upon completion restoring the right of way to the mainhighway or boulevard. However, this system is not satisfactory atintersections where the traiiic is variable on the several streetsforming the intersection, nor at intersections where the traic issubstantially uniform on all of the streets constituting theintersection:v

In accordance with the present invention a v trailc regulating system isprovided which is adaptable for use at any intersection, having all theadvantages of the pre-fixed timer. the semiactuated, and the fullyactuated systems, and in addition, being capable of automaticallyaccommodating, changing tramo conditions whether vso hourly, daily, orseasonally, and which embodies many improvements whereby the dispatch oftrafllc of any nature and volume may be facilitated in .accordance withthe requirements of the traffic itself or the requirements of thelocality through which the traffic is passing. At the same time, the owof traiiic is automatically maintained within predetermined speed limitsto prevent speeding and especially racing of operators of vehiclestoward an intersection in an effort to negotiate the intersection beforethe clear or go signal facing the street upon which the racing vehicleis traveling changes to the warning or stop signal.

The system of this invention includes detector devices in or adjacentthe streets constituting the intersection which are responsive to thepresence of traiiic approaching the intersection in order to negotiateit, these detector devices, upon actuation by a unit of trafc, whethervehicular or pedestrian, establishing a circuit to corresponding memoryrelays which remember that a unit of traiiic is seeking to negotiate theintersection and accordingly appropriate control of the signal cycle topermit the passage of the corresponding vehicle upon completion of thesignal cycle which was in progress at the time that the correspondingvehicle actuated the detector device and established a circuit to thecorresponding memory relay. Vehicular detector devices are preferablylocated in the surface of the streets forming the intersection and thepedestrian detector devices are preferably located at or adjacent thecorners of the intersection, both vehicular and pedestrian detectorshaving relays which have the same function, i. e., they prepare acircuit which is completed upon completion of the signal cycle then inprogress to permit passage of the intersection by-the initiating unit oftramo at the proper time.

The mechanism which is energized by the memory relays in response toactuation by the detector devices includes a selector switch whichselects predetermined circuits for performing various functions,depending upon pre-arrangement of the system and upon the nature andvolume of the traffic seeking to negotiate the intersection. Forexample, the selector switch prepares circuits to timing mechanism whichdetermines the duration of the signal cycle in accordance with certainpredetermined considerations, one of which is the duration of theinitial period of time during which the right of way is maintained forone or more streets or a highway or boulevard, and another of which isthe duration of the extended period of time during which the same rightof way is maintained y 'I'he initial period is adjustable in accordancewith observed traffic conditions, i. e., the initial period may beshortened or lengthened in accordance with the volume of trailic whichit is desired to negotiate an intersection during any one signal cycle.During this initial period, the trafiic units crossing detector devicesare rendered ineffective or prevented from interfering with the signalmechanism to appropriate control thereof, but after termination of theinitial period, the actuations by other units of trafficbecomeeffective.

'I'he extension period is determined by traffic seeking to cross theintersection on the street having the right of Way upon termination ofthe initial period, and the number of units of time comprising theextension period is determined by trafilc units following the trailicunit which originally initiated the extension period on the street whichhad the right of way during the previous initial period, but the maximumnumber of units of time by which the extension period may be lengthenedis predetermined manually. In other words, within certain limits, theduration of the right of way on any street may be extended as many unitsof time after the termination of the initial period as 'there are unitsof traiilc following the traffic which negotiated the intersectionduring the initial period.

During the additional units of time forming the extension period, massedtraffic, single units of traic, or any intermediate number of units oftrailic, may negotiate the intersection without affecting vthe timeextension mechanism, and it is only during each extended period of timethat a following unit of tramo may set up an additional unit of time tofurther extend the extension peri= od. That is to say, during theextension period, except at predetermined moments, the devicesresponsive to traffic are locked against actuation by the traffic or arerendered ineffective to interfere with or otherwise aiect the signalmechanism.

If there has been no actuation of detector devices by pedestrian or byvehicular trafiic approaching on a street other than that having theright of way, prior to termination ofthe initial and extension perids,as remembered by the corresponding memory relays, the street previouslyhaving the right of Way maintains the right of way. If one of the memoryrelays has been actuated at or previous to the time when the initialperiod expires, or when the extension period expires if set up, theright of way is eventually transferred to a pedestrian or to the streeton which the initiating traffic is waiting to cross the intersection.

Located in one or more or all of the streets forming the intersectionare devices responsive to the speed of traffic approaching theintersection on the corresponding street, which, if the traffic ismoving at a speed less than the predetermined speed limit, are notaffected, but which, if the trafiic exceeds a predetermined speed limit,respond 'to appropriate control of the right of way for that street andflash a stop signal against the speeding traffic without interruptingthe signals displayed to the trafiic approaching the intersection on theother streets thereof. The stop signal halts the speeding vehicle beforeit can negotiate the intersection and is maintained a. sufficient timeto perform its function, when it becomes inoperative and the signal forthat particular street is restored to the same condition in which itwould have been had the signal cycle for that street not beeninterrupted by the speeding vehicle.

In order to convert the fully actuated traffic regulating system justdescribed into a semi-actuated system, switching devices are providedwhereby the detector devices of the streets which are selected to bemain highways or boulevards are disabled and means are provided wherebythe right of way or normal go signal is restored after each signal cycleto the street which has been selected as the main highway or boulevard,the detector devices in the other streets remaining responsive totraffic approaching the main highway or boulevard in order that theright of way may be transferred t0 this trafiic for negotiation by it ofthe main highway or boulevard. In this way, the system of this inventionmay be readily converted from a fully-actuated system to a semiactuatedor normal go system, and vice versa.

iii

iti

iid

dit

vthis invention, the signal itlso. by means of the switching devices allof the detector devices may be disabled to convert the system into aprefixed timer system wherein right of way is alternately transferredfrom one street to another and back again.

llhe detector devices which respond to the presence of pedestrian orvehicular tramo are included in normally closed circuits which arebroken when the detector devices are actuated to control correspondingdetector relays which in turn control the corresponding memory relays.This arrangement provides extreme sensitivity and accuracy as well asbeing immune from local iniiuences which tend to disable open circuitdetector devices, such as corroded contacts and short circuits. However,in the arrangement of mechanism is not disabled if the detector circuitsstick open or are otherwise inoperative, for in that event the systemimmediately becomes a pre-fixed timer system as to the street having thedisabled detector circuit.

titre present invention further provides for a system ior control byeither of the two intersecting streets and by pedestrians which alordsthe utmost flexibility with respect to the flow of tramo. If there is ademand for the right of way simultaneously by the two streets andpedestrians, the present invention will successively accord the right ofway to the streets and to the pedestrian trafic. if this demand, shouldbe omitted by the secondary streets or by pedestrians. the signal willautomatically eliminate the corresponding right of way period so thatthe signal will operate alternately between the primary street and theremaining traic path. It is also possible to substitute for one of theintersecting streets an additional pedestrian lane or by simply omittingone vehicle detecting device ot the secondary streets to utilize thepresent invention for the intersection of a pedestrian cross walli inthe middle of a block where no cross vehicular trame can iiow. In such acase, the invention automatically eliminates the corresponding timeinterval in exactly the same manner that it would under lighter trailicconditions; that is, the pedestrian traffic will have the right ci wayfor a certain predetermined minimum period and possibly for a furtherperiod not to exceed a predetermined maximum depending upon the densityof pedestrian trailc. At the expiration of the pedestrian interval, theVehicular traiiic may again obtain the right of way for a predeterminedminimum period and for such extensions beyond the minimum period asconditions of traffic` Ilow mayv require but not to exceed apredetermined maximum period.

It will be seen that with the tralc system of this invention any;traiiic conditions may be handled expeditiously and with preciseconsideration of the volume and nature of the traillc and the changes inthe volume and nature of the trame at any time. Thus, the system of thisinvention can be mounted at any intersection and readily adjusted at anytime to conformto the trame requirements of the intersection or localityin which it is located. Fora. more complete understanding of theinvention, reference may be had to the accompanying drawings. in which-Figures 1, 2, and 3 jointly illustrate the complete schematic circuitdiagram oi the selective and automatic trame regulating mechanism ofthis invention, the three sheets of drawings on which these iguresappear being arranged to be laid side by side to form one completediagram.

Solely for the purpose of facilitating the tracing of leads from Fig. 1to Fig. 2 and from Fig. 2- to Fig. 3, the several -leads have beenmarked with the characters of the alphabet to identify them as theyenter and leave each iigure. No further reference to these characterswill be made.

Fig. 4 illustrates the arrangement of the 4initial and extension periodcounting mechanism.

Referring to the drawings, Fig. 3 indicates the intersection of twothrough streets crossing at right angles. 'I'his form of intersection isemployed for the purpose of illustrating the application of theinvention to a typical intersection, it being understood that theinvention is applicable with equal facility to Y, T, or other forms ofintersection. Also for convenience, traiic lanes which pass entirelythrough an intersection whether on the straightway or whether they curveor are bent at an angle are called main highways, through streets, orboulevards, while those tramo lanes which terminate at the intersectionare designated as streets irrespective of whether such traiiic lanes mayor may not be a component part of a trafc lane passing through theintersection and designated a highway. Thus, in Fig. 3, the throughstreet, boulevard, or highway which runs north and south consists o! twostreets terminating in the intersection and these streets are designatedas #l street and #3 street, while the two east and west streets aredesignated as #2 street and #4 street. Suitably located at theintersection and clearly visible from all approaching streets is atleast one visual signal device of conventional design including green,amber, and red lights for each street or traiic lane. or the like. Thelights which tace #l street are designated for convenience G-L AI, andRf-I., the lights which face #3 street are designated G--3, A--B and R3.Similarly, the lights which face #2 street are designated G-2, A-2, andRf-2, and the lights which face #4 street are correspondingly designatedGh-l, A-4, and R-I.

The trame control mechanism is adapted for energization by a commercialsource of alternating current although by readily understoodmodifications, it could be made suitable for operation on directcurrent. Since in ordinary commercial practice it is customary to groundone side of the supply, all points on Figures 1, 2. and 3 whichareconnected to the grounded side of the commercial supply have beendesignated by the conventional symbol for ground. Those parts of thecircuit which are connected to the opposite ungrounded side of thecurrent supply have been designated by the character AC in a circle.Thus, in tracing any path of current ow, it must begin at AC and end atground.

THE TRAFFIC DE'rEcrrNc DE'vroEs Located on the right side of #1 street,preferablyV in the surface of the roadway so as to be responsive tovehicles passing thereover, is a detector 50 comprising a plurality oflight segments 5I, each carrying a contact 52 normally engaging acorresponding Contact 53, these contacts being connected in series withwires 54 and 55. A similar vehicle detector 50 comprising segments 5| islocated in the surface of the right hand side of #3 street. Thesesegments 5I each control a set of closed contacts 52' and 53'. which areconnected in series with the contacts of detector 50 and with relay 56through the wires 54, 55, and 55. These vehicle detectors are formed insegments 5| and 5 I so that more rapid, effective and simpler responseby a vehicle passing either one of them 1s obtained than if the streetdetector were a longer strip that is necessarily bodily movable in itsentirety to close a contact in response to actuation by a vehicle. Asindicated, and as will more fully appear, the circuits of all detectorsare closed so that they cannot be short-circuited by dirt, ice, or snow,or the like accumulating between contacts as is the case with opencircuit detectors and a surer, more positive response results since itis ordinarily easier to break a circuit than to make one. Furthermore,as will be explained later, even if the detector circuitsI of thissystem are broken or the detector contacts stick open for any reason,the traic system is not disabled but automatically provides a fixed timeinterval with respect to the street having the open detector circuit;that is, in such a case, the street having the disabled detector willalways obtain and hold the right of way for its full maximum period andafter transfer of the right of way to an intersecting traffic movement,the right of way will automatically return to the street of the disableddetector device and will remain there again for a full maximum periodbefore it can be retransferred to an intersecting traffic lane.

Wire 55 leading to #1 detector relay 56 is connected through coil 51 toone side of a rectifier 58 and wire 55 is connected to the opposite sideof rectifier 58. A variable resistance 59 between coil 51 and rectifier58 permits adjustment of the current intensity and resulting magneticpull developed in coil 51. The input or alternating current side ofrectifier 58 is connected to the secondary winding of a transformer 60,the primary of which is connected to the alternating current supply,designated by the symbols AC, and ground. In actual practice, thetransformer 60 delivers approximately 11/2 volts of alternating currentto the rectifier which in turn has an output of approximately 20milliamperes at a direct current potential of one volt which isimpressed upon the detector circuit including coil 51. A light needlearmature 64 is normally held disengaged from stationary contact 62 bythe attractive force of coil 51 and is continuously urged intoengagement with contact 62 by the light spring 63 so that upondeenergization of coil 51 armature 64 will establish a contact withcontact 62, such deenergization occurring upon operation of one of thedetectors 50 or 50 by the passage of a vehicle.

The surfaces of the roadways of #2 street and #4 street are providedwith similar vehicle detectors 500 and 500 which, when actuated, breakrespective closed contacts 520 and 530 or 520 and 530' connected inseries to wires 540 and 550 leading to #2 detector relay 560 which islike #l detector relay 56 in all respects and is therefore notillustrated in detail.

SELECTOR SWITCH I Included in the tra'ic regulating system of thisinvention is a circuit selector switch 65 which is illustrateddiagrammatically in Fig. 1 and which comprises a shaft 66 rotatable byan eddy current motor 61, or the like, and carrying a plurality ofspaced cam discs 68, each effecting the engagement and disengagement ofa pair of contacts which are numbered serially from one to twenty-sevenon Fig. 1 of the drawings for convenience. As the selector switch 65 isrotated periodically by the motor, its cams 68 close cer- ,tain of thesets of contacts and open others to select certain correspondingcircuits for operation and open other corresponding circuits. 1n apreferred arrangement the selector switch has eight positions in each ofwhich certain contacts are closed and the signal lights are energized inaccordance with the following table:

First position At rest for G-I and G-3 #l street and #3 street green(G-|, G-3) #2 street and #4 street red (Rf-2, R-4) Contacts: I-3--8-9- I|J l 4--2 2-2 3 closed Second position Timing A-l, A--3 interval #lstreet and #3 street amber (A-I, A-3) #2 street and #4 street red (R-2,R4) Contacts: 5-1-8-9-I 0 2 I-2 2-21 closed Third position Timing G-2and G--4 interval #l street and #3 street red (Rf-I, R-3) #2 street and#4 street green (G-2, G-4) Contacts: 4-9-I0--I2-I1-I8-I9 closed Fourthposition At rest for G-2 and G-4 #1 street and #3 street red (Rf-I, R-3)#2 street and #4 street green (G-2, G-4) Contacts: 2-3-8-9-10-15-l8--I9closed Fifth position Timing A-2, A-4 interval #l street and #3 streetred (R-l, R-3) #2 street and #4 street amber (A-Z, A-4) Contacts:6-1-8-9--l ll-I 6--I 9-20 closed Sith position Timing all red interval#l street and #3 street red (R-I, R-3) #2 street and #4 street red (R-2,R-4) Contacts: 1-6-9-I0-I9-22-26 closed Eighth position Timing G--l andG-3 interval #l street and #3 street green (G-I, G-3) #2 street and #4street red (Rf-2, R-4) Contacts: 8-I0-l I-22--23-24 closed Relay H4 isadapted to energize selector switch motor 61 upon closure of itscontacts H6, this current being supplied from AC at armature H6, contactIll, wire IIB, and the motor Windings to ground. Mechanical provision ismade so that a single impulse energizing relay H4 will positively keepcontact I I1 closed until the switch has completely advanced to the nextposition. The mechanism for effecting this positive action is notillustrated but it may be of any conventional type. The purpose of thisrelay is to permit a circuit energizing relay H4 through a selectorswitch contact which will open during the passage of the selector switchto its next position to positively complete the travel of the switchuntil the next position has been reached. Without this arrangement, theselector switch would stop immediately upon the opening of the selectorswitch contacts through which energy was being received and this wouldnecessarily cause the switch to stop in a position intermediate tointended positions and might readily disrupt the control of traiiic bythe mechanism.

SELECTOR SWITCH FIRST POSITION Assuming that #l and #3 streets have theright of way, i. e., that the selector switch 85 is in the firstposition indicated in the foregoing table and that a vehicle approachingthe inter section on #l or #3 street actuates the vehicle detector 50 or50 to operate #1 detector relay 56 so that its armature 64 engagescontact 62 in a manner described above. Since #1 and #3 streets alreadyhave the right of Way, nothing happens except that #1 memory relay 80 isenergized by a circuit traceable from AC at contact 62 of detector relay56, armature 64, wire 13, to terminal 14 where the circuit divides, onebranch following wire 16 to terminal 11 where the circuit again divides,one branch leading by wire 18 to coils 19 of #1 memory relay 80. thecircuit of which is completed by the indicated connections to ground.Armature 84 of memory relay 80 is accordingly drawn into engagement withfront contact 85 and breaks back contact 86. The other branch circuitslead to open contacts and need not be described. The bridging ofcontacts 85 by armature 84 of memory relay 80 establishes a holdingcircuit therefor which is traceable from AC at pigtail 84', armature 84,

f contact 65, wire 94, closed contact 9 of selector switch 65, wire 95,terminal 11, wire 18, and coil i9 ci relay 80, back to ground. Thus,memory relay remains energized until such time as selector contact 9opens and for a further period described below. The circuits of thecoils of all memory relays include a series combination of condenser andresistor connected in multiple with the relay Winding for the purpose ofreducing the amount of arcing which will occur at the contacts 62 anddelicate needle. armature 64 of the various detector relays.

Assuming that, with the selector switch in the first position, #3 and #lstreets having the right ci way, as indicated in the foregoing table, a

vehicle approaching on either #2 or #4 street actuates respectivevehicle detector 500 or 500', #3 detector of relay 560 releases itsneedle armature to connect AC to wire 91 and initiate a circuittraceable from wire 91 to terminal 98 where the circuit divides, onebranch leading by wire 99 to one terminal of the #2 memory relay |00,the other terminal of which is connected to ground. The armature |02 ofmemory relay |00 accordingly bridges its front contacts |03 and |03 andbreaks back contacts |04. Energization of memory relay completes aholding circuit for the relay and also a circuit to selector switchmotor 0i. The holding circuit has two shunt paths, one traceable from ACat pigtail |06, armature |02, front contact |03, wire |01 to terminal|00, branch wire |09, closed contacts 0, controlled by the follower ofcam 89, terminal 98, wire 99, and relay |00, to ground; and the othershunt path is traceable from terminal |08 by wire 28 to closed contacts8 of selector switch 55, wire 29, memory relay |00, and ground. Theselector switch motor circuit is traceable from AC at pigtail |06 memoryrelay |00, armature |02, relay contact |03', Wire ||2, closed contact ofselector switch 65, wirel I3, relay H4, and ground. Upon energization,relay I4 pulls its armature ||6 into engagement with contacts ||1,completing a circuit for the selector switch motor, as described above.The fact that selector contact is the source of energy for relay ||4 andthat it opens when passing from the first to the second selector switchposition is taken care of by the operation of relay |I4 together withlocking feature, as described above, so that the selector switch willadvance positively to its second position.

SELECTOR SWITCH SECOND PosI'rIoN Selector switch motor 61 rotates to ltssecond position, its contacts, listed in the foregoing table, beingclosed. Those contacts which were listed as closed in the first positionand as omitted in the second position are opened by operation of thecams during the travel of the switch from its first to its secondposition. Those cams not listed as closed in the rst position but whichappear as closed in the second position close their respective contactsduring'the travel of the switch from its first to its second position.Thus, by reference to the table. it can be readily determined which ofthe contacts are closed, those that are open, and those which changetheir condition during the travel of the switch.

In this movement, from first to second position, the selector switchopens the circuit of the #l and #3 streets, green lights, G-I and G3,but maintains the circuit of the #2 and #4 streets, red lights, R--2 andR-4. The circuits of these lights are controllable by respectiveselector contacts 23 and 22, the red light circuit being traceable fromAC at pigtails 20 and |2|, of respective parallel relays |22 and |23,their armatures |24 and |25, their closed back contacts |26 and |21,wires 28 and |28, selector contact 22, to terminal |3|, a branch WireN32, red lights R--Z and IiP-4, and to ground, and wire |36 leading fromselector contacts 23 to terminal i31 where the circuit divides, onetraversing wire |38, relay contacts |39, and armature |40 to lamp G-iand ground. and lthe other branch traversing wire |4|, relay contact|42, and armature |49 to light G-3, and ground. Thus, when contact 23 ofselector switch 61 is broken as the switch moves to its second positionin the manner described, the green lights G-l and (3i- 3 which signalthe right of Way to tralc on #l and #3 streets are extinguished but redlight R-2 and R-4 remain energized because selector contacts 22 remainclosed. The selector switch 65, in moving from iirst to second position,also breaks its energizing circuit by breaking selector contact i,releasing relay H4, so that the selector switch 65 stops in the secondposition. The selector switch 55 maintains contact 8 closed in bothpositions i and 2 so that the holding circuit of memory relay 00 whichincludes this selector contact will remain closed. The closing ofselector contacts 21 completes a circuit traceable from AC at pigtails|20 and |2| of relays |22 and |23 and their armatures |24 and |25through their back contacts |26 and |21, all respectively to wire |28,terminal |41, wire |29, selector contacts 21, wire |48, terminal |49,where the circuit divides, one branch leading to parallel relays |50 and|5| and ground, and the other branch from terminal |49 following wire|53, to normally closed contacts |54, controlled by cam |55, to amberlight motor |56, wire |51 to terminal |58 where the circuit divides, onebranch follow-ing wire |59 to amber interval timing motor |58 andground. Amber interval timits mechanical intering motor |56 accordinglybegins to make one complete revolution at the end of which it breaks itsown circuit by opening contacts |54. The other branch terminal |58follows wire |6| to front contacts |62 of relay |50 which were bridgedby armature |63 when the relay was energized by closure of selectorcontacts 21 in the manner described. The armature of relay is 'connectedto AC at pigtail |64 so that when relays |50 and |5| are energized inthe manner described, upon closure of selector contacts 21, causingarmature |63 to engage front contacts |62, a holding circuit isestablished for relay |50 which is traceable from contact |62, wire |6|,terminal |58, wire |51, normally closed contacts |54, wire |53, terminal|49, and relays |50 to ground.

The closure of relay |5| establishes a circuit traceable from AC atpigtail |1|, armature |12 of relay |5|, contact |13 of relay |5|, wire|14, terminal |15 where the circuit divides, one branch traversing wire|16 to terminal |11 where the circuit divides, one branch leading tocontacts |18', bridged by armature |18 to amber light A-3 and the otherbranch leading to contacts 19, bridged by armature |80, to amber light`A|, both lights A--l and A-3 being connected to ground. Thus, the amberlights are lighted, serving as a warning to trailc approaching theintersection on #l and #3 streets. The other branch of the circuit from-terminal |15 is traceable through wire |8|, closed contacts 2|, andselector switch 65, wire |29, terminal |41, closed back contacts |26 ofrelay |22 to AC at pigtail |20; the other branch circuit from relay |5|may be traced from AC at pigtail |1|, armature |12, contact |13, wire|85, terminal |3|, where the circuit divides, one branch following wires|32 to red lights R-2 and R-4, so that relay |5| maintains the redlights against trac on #2 and #4 streets, in addition to the display ofthe amber lights A-I and A--3 to #l and #3 streets. Upon beingenergized, amber interval timing motor |56 makes one complete revolutionof its cam shaft.

When energized, amber motor |56 begins to make one complete revolution.Before the revolution is entirely completed, the cam contacts |86 closeand reopen, completing a circuit to advance selector switch 65 fromposition 3 to position 4 by energizing relay ||4 by a circuit which istraceable from AC at pigtail |64 of relay |50 through upper contact |62,along wire |66 to cam follower |61 which engages cam |69, and uponentering the notch in cam |68, contacts |86 close and the pathpreviously traced from AC continues through wire |81, wire |66, selectorcontacts 1 which are in position 2 and along wire |3 to the winding ofrelay I4, and to ground. Relays |50 and |5| remain operated, sincealthough cam contact 21 has opened, breaking one of the parallel holdingcircuits, the circuit along wire |6|, to contacts |54, still remainsclosed. Shortly thereafter, and after selector switch 65 has hadsuicient time to advance to its third position, normally closed contacts|54 open momentarily, breaking the holding circuit for relays |50 and|5|, via wire |6|, and these relays now release. The selector switch,however, is now in the third position, and the change of lights will bedescribed below. In order to insure that amber interval timing motorwill continue to run for a sufficient period to positively permitcontacts |54 to reclose, contacts |81 will be closed during the timethat contacts |54 are opened and will remain closed until after contacts|54 are also tact I8, wire |94, to terminal |95 closed. Contacts |81will open very shortly after contacts |54 have closed. During theinterval that contacts |81 are closed, a path is traceable forenergizing the upper winding of amber interval timing motor |56,beginning with AC at I pigtail |64 of relay |50 which has been releasedSELECTOR SWITCH THIRD POSITION Selector switch 65 has already advancedinto its third position before the relays |5| and |50 A have released.In the third position, as soon as these relays close their backcontacts, a circuit to the amber lights, A-I and A-3, will be broken atthe upper contact |13 of relay |5|, and the circuit of red lights, R-2and R-4, will be broken at the lower contact |13 of the same relay. Assoon as the back contacts close, a circuit is traceable from AC atpigtail |64, through the closed back contacts, wire wire |93, throughclosed selector contacts |9 and wire |92, terminal |90, wire |9|, tolights R-l and R--3 and ground. Simultaneously therewith, a circuit fromwire |93 may also be traced through closed selector conand throughbridged contacts |91 and 200 to lights G-2 and G4 respectively. Thus,the releasing of relays |50 and |5| has the effect of switching lightsfrom A-l and Rf-2 to R--I and G-2. Memory relay |00 remains held in,although selector contacts 8 are open in selector switch position #3.

This circuit may be traced from AC at pigtail |06,

through closed contacts |03, terminal |08, wire |09, closed cam contactsI0, terminal 98, wire 99, back to the coil of relay |00 and to ground.In the third selector position, relay |00 is held in through closedcontacts on #l and #3 streets is R-l and R-3 and right away trafcwaiting on #2 and #4 streets play of green lights G-2 and G-4.

TIMING MEcHANIsM The duration of the signal cycle is timed from now onby timing motor 202, the circuit of which is controlled by closedcontacts |1 of selector switch 65. The circuit of the timing motor istraceable from AC at pigtail |64 of relay |50, its armature |63, itsclosed back contacts, wire |93, closed contacts |1 of selector switch65, wire 203, terminal 204 where the circuit divides, one branch passingalong wire 205 to the lower pair of windings of the timing motor 202.and to ground. The timing motor 202 accordingly begins to revolve. Theother branch of the circuit from terminal 204 follows wire 201 to magnet208 of the time limiting mechanism to ground. Energization of magnet 208causes it to draw its armature pawl 2|0 into engagement with ratchetwheel 2| which is secured to a shaft 2 |2, carrying cams 2|3 and 2|4.The cams 2|3 and 2|4 may be independently adjusted manually byadjustment levers 220 and 230, shown in Fig. 4, into any angularposition relatively to leach other and relatively to the ratchet Wheel2|| so that a greater or lesser number of revolutions of the timingmotor 202 will be required to rotate the is transferred to by the dis-||0. Traffic approaching. halted by the red lights' cams 2|3 and 2|4 toa position where they will close their respective contacts 2|0 and IIB.The means for rotating shaft 2|2 comprises a wheel or equivalent device2|'I mounted on shaft 2I0 of timing motor 202 and arranged to engageratchet wheel 2li by means of pin 2|1 to advance wheel 2|| one notch foreachrevolution of timing motor 202 in a manner readily understood.Armature pawl 2 |0 serves to hold ratchet wheel 2|| in any advancedposition during such l time as magnet 208 is energized. The foregoingpin 233 at its free end, adapted to be engaged in any one of a series ofnotches 234 formed in the disc 235 except the notch occupied by thelocking pin 236 of initial period adjusting lever liti 220 and thosenotches between initial period locking pin 236 and the lowest index ofdisc 235. By stop means 220', the movement of the initial periodadjusting liever 220 is restricted to four positions although it mayhave a greater or lesser number of positions depending uponrequirements. The maximum period adjusting lever 230 may have any one ofa number of positions beginning with the notch 234, next to the stop 220for the initial period adjusting lever 206, and ending with the notchmarked I3, for example, although the lever may be movable to any othernumber of positions. In the particular arrangement illustrated, allnotches 234 represent uniform periods of time, the initial period havinga duration of one, two,three, or four revolutions of the timing motorand the maximum period has such an additional number of revolutions ofthe timing motor as may be determined both by the setting of adjustinglever 230 and conditions of traiilc ilow, the smaller of these twopossible numbers of revolutions being controlling, as will be set forthin greater detail below.

Two similar pairs of electro-magnets are provided, being illustrated inFig. 2 schematically, one pair being drawn above the shaft 2|8 and theother pair below. The upper portion of the timing motor is associatedwith or is used for the purpose of controlling the duration of G--I and@-3 interval and the lower portion is used for controlling the durationof the G--2 and Cil-4 interval. The adjustable pole pieces 244, as shownin Fig. 4, are provided in duplicate, the upper-set permittingindependent adjustment of the duration of one revolutiton of cam shaft2|8 while the G-I and G--3 interval is being timed, and the lower set,not illustrated in Fig. 4, is independently adjustable and controls theduration of one cam shaft revolution while timing the G-2 and G 4interval. Independent magnets 35| and 208 determine which of the initialand maximum intervals of timing mechanisms shall be advanced during theoperation of the timing motor since it will be observed that unless oneof the magnets is energized, the two whieels 2|| and 353 will drop backto their initial position after each engagement with pin 2|1' of wheel2H.

Tm; INITIAL Pmron The timing motor 202 controls the timing of greenlights for all four streets and when it is energized, it rotates cam 2|4during the timing of the G--2 and (EI-4 interval in the third selectorposition. The angular position of cam 2|4, which is determined by thesetting of initial period adjustment lever 220, shown on Fig. 4,determines the number of revolutions of timing motor 202 required toeffect closure of contacts 2|B. The minimum time during which the lightsG-2 and G-4 will be displayed is determined by the number of revolutionsof motor 202, operating on its lower windings, which will be required toallow contacts 2|6 t'o close, and this is termed the initial'period.This period insures s that all vehicles, following the vehicle whichinitiated the signal cycle and brought the selector switch to-its thirdposition, and which following vehicles have already passed the detectors500 and 500', will be assured of an opportunity to traverse completelythe intersection before the signal can be changed, without necessitatingof any operation of the extension mechanism. That is, the initialperiod, when the right of way is first accorded by the timing mechanism,ends when cam 225. to be referred to presently, first closes itscontacts 224 after closure of contacts 2| 5 by virtue of the operationof cam I4 which must ilrst have reached the requisite positiondetermined by the setting of initial period adjustment lever 220. Acircuit energizing the f lower portion of the timing motor is traceablefrom AC at pigtail |20 of relay |22, closed contacts |25, terminal |41,wire |29, closed selector contacts Il, wire 203, terminal 204 where thecircuit divides, one branch traversing wire 201 to energize magnet 208,attracting armature pawl 2|0 in a position to retain toothed wheel 2||in an advanced position. The other branch passes along wire 205 to thelower driving winding of the timing motor 202 and to ground. Theenergization ofthe driving winding of the timing motor 202 causes shaft2|8 to rotate. Shortly after it begins its revolution, cam 89momentarily opens normally closed contacts H0, breaking the holdingcircuit for #2 street memory relay |00, through wires |09 and 99. Thisrelay is thereupon released, and a circuit is traceable from AC atpigtail IUSthrOug-h armature |02, the closed back contacts, wire 22|,wire 222, through the closed contacts of selector contact I 2, Wire 223,to the open contacts 2|6. At the end of each revolution of cam shaft2|0, cam contacts 224 close momentarily. Contacts 359, 355, and 2|5 areall open at this time, the contacts associated with the upper timingmechanism for #l street being unable to close because toothed wheel 353drops back each time it is engaged by pin 2|1, since magnet 35| isdeenergized and the pawl 352 cannot hold the toothed wheel 353 in anadvanced position. The contacts 2li are associated with the maximumtiming mechanism to be described below, and will not close until aftercontacts 2|6 have closed. After the predetermined number of revolutions,comprising the initial interval,cam contacts 2| 5 will close; and at theend of the last revolution of the series constituting the initialinterval, upon closure of cam contacts 224, AC, which has already beentraced to contacts 2|6, will be applied to wire 226, wire 221, and thewinding of selector switch relay ||4, energizing relay ||4 and advancingthe selector switch to the fifth position.

EXTENSION PERIOD Returning to the situation with the selector switchstill in its third position, either traiflic on #l or #3 street or apedestrian, or continuing traiiic on #2 or #4 street may control thesignal mechanism, the first of these by transfer of control from the #2and #4 streets, and the latter by maintaining control by the creation ofextension periods. Before an extension period may be added to theinitial period, #2 memory relay must be prepared for reactuation, whichrequires that it must first be released. This is done by the momentaryopening of contacts ||0 of the timing motor 202. Shortly after thetiming motor 202 began to rotate, the holding circuit for #2 memoryrelay |00 momentary interruption, thus releasing the memory relay. Withthe memory relay |00 in this condition, it is capable of beingreoperated and thereby establishing an extension period for #2 and #4streets, and this effect may be obtained by the actuation of eithervehicle detector 500 or 500', by the passage of a vehicle on #2 or #4street. If memory relay 00 is released, and remains in this conditionuntil initial period cam 2|4 has closed its contacts 2|6, the durationof G-2 and G-4 will be terminated as described above, the circuit ofselector switch relay ||4 having already been prepared for energizationby any subsequent closure of contacts 224 which are responsive to cam 25of timing motor 202. However, if memory relay |00 is reoperated duringthe interval intermediate the opening of cam contact ||0 and the closureof cam contacts 224, it will disconnect AC from wire 22| and contacts2|6, and the circuit to the selector switch relay ||4 will no longer becompleted upon closure of contacts 224 and advancement of the selectorswitch to its fourth position will be delayed until the next subsequentclosure of contacts 224. During this time, any movement of vehiclesacross the vehicle detectors 500 and 500' .can have no effect on thesignal circuit, since #2 memory relay |00 is already energized and hasnot yet been released by the opening of cam contacts |0 at the beginningof the next subsequent revolution of the timing motor. Thus, it will beseen that a vehicle causing the operation of memory relay |00 during thefinal revolution of cam shaft 2|8, in the course of the initialinterval, may secure for itself one additional revolution of the camshaft 2|6 in which this vehicle will be aiiorded a continuingopportunity to traverse the intersection. This opportunity to obtain anadditional period exists only during the last revolution of the initialperiod, because if the initial period consists of more than onerevolution, it will be only during the last portion of the lastrevolution that cam contacts ||0 will remain closed and retain anyprevious operation of #2 memory relay |00 which has been secured byactuation of the vehicle detectors 500 and 550. During the iinalrevolution of the initial period, the system may be caused to maintainthe right of way on #2 and #4 streets for one additional revolution ofcam shaft 2|8.

If, in the course of this additional revolution, and during the intervalbetween the opening of contacts ||0 and the closure of contacts 224, anadditional impulse is received, relay |00 will again operate and willhold in, deenergizing contacts 2 6 and preventing the selector switchfrom advancing when contacts 224 close at the end of the revolution ofshaft 2|6. In this manner,

was broken by this` a second extension period may be obtained by avehicle operating #t2-street memory relay 00 during the latter portionof the first extension period. Correspondingly, a third extension periodmay be obtained by the passage of a vehicle across detectors 500 or 500'during the latter portion of the second extension period and thisprocedure may be repeated indefinitely until cam contacts 2|5 close.Upon closure of contacts 2|5, a circuit is traceable from AC throughwire 241 and wire 223 to .contacts 224, so that upon the next closure ofcontacts 224, selector switch relay 4 will be energized by a circuitincluding wire 226 and wire 221, and will advance the selector switchfrom its third to its fourth position, even though #2 street memoryrelay |00 may still be energized. If #2 street memory relay should beenergized, it will remain held in through closed contacts ||0 which havenot yet opened and also through the auxiliary holding circuit, includingselector contacts 8 which are closed in all but the third selectorswitch position.

Only in the third selector switch position, canA #2 street memory relaybe released by opening contacts ||0.

It should be observed that the duration of the interval between theopening of contacts ||0 and the closure of contacts 224 is sufficient sothat any vehicle passing detector 500 or 500' before contacts ||0 haveopened will have sufilcient time to clear the intersection. Otherwise, avehicle might approach the intersection before contacts ||0 had openedand prepared relay |00 for reoperation, and because of the shortinterval, it would not have an opportunity to clear the intersectionbefore the closure of contacts 224 and the immediate advancement of theselector. Furthermore, it would not have registered its presence,because at the time of its passage over the vehicle detectors, relay |00had not yet been released and consequently was incapable of reoperatingand registering an actuation of the detectors. Any extension period, asdescribed above, can be obtained only during the course of the lasttiming motor revolution of the initial period and during each subsequentextended period, the number of possible extension periods being limitedonly by the closure of cam contacts 2|5, this number of revolutionsbeing determined by the setting of maximum period adjustment lever 230.As the selector advances into the fourth position, the path for theenergization of the lower winding of the timing motor is interrupted .bythe opening of selector contact |1. However, in order to insure that themotor will travel a suilicient distance to open positively contacts 224,the cam 605 is provided. A circuit is traceable from pigtail |64 ofrelay |50 through the closed back contacts along wire 60|, wire 602,wire 606, through contacts 601, wire 608, wire 609, closed selectorcontacts I5, wire 6||, wire 203, terminal 204, and wire 205, to thelower driving winding of timing motor 202. Cam 605 is so adjusted thatcontacts 601 open later than contacts 224, and consequently motor 202will not stop running until contacts 601 have opened, although this maybe a very small fraction of a second later than the opening of contacts224. It has the effect, however, of always bringing shaft 2|8 into thesame position for the beginning of each series of timing revolutions. Assoon as contact 601 opens, the driving winding of timing motor 202 isdeenergized and 'magnet 208 is also deenergized, releasing pawl 2|0 andallowing toothed wheel 2|| to be restored to its normal position by theiniiuence of coil spring 240, illustrated in Fig. 4. This opens contacts2|5 and 2|6 so that there will be no interference with the timing of theG-I and G`2 It is essential that these contacts be opened since both theupper and lower portionsof the timing motor utilizes the same contacts224 to advance the selector switch at the end of the corresponding greentiming period.

SELECTOR SWITCH FoUnTH PosrrroN 'The fourth position of the selectorswitch is a position at which it will remain in the absence of actuationby pedestrians or by trail'ic on streets #i and #3. It corresponds inthis respect to position #l of the selector switch. In the fourthposition of the selector switch, extension periods cannot be set up toextend the right of way for #2 and #4 streets but pedestrians or trafllcon #1 and #3 streets can immediately assume control oi' the system.Assuming that #l streets memory relay is energized, a holding circuit isestablished through selector contact #9, which is closed in allpositions except position 8, and consequently it will remain held inthrough this path, including wire 18, terminal 11, wire 19, closedselector contact 9, wire 94 and contact 65. Il' #l memory relay 80 isenergized, the selector switch will be advanced to the iifth position bya circuit traceable from AC at pigtail 84', armature 84, upper contact85, wire 93, closed selector contact 2, and wire H3 to selector switchrelay 4 and ground. Ii', instead, the pedestrian relay P is energized,it will be held in a manner to be described below, and a circuit toadvance the selector switch to its iifth position is traceable from ACat pigtail 260, armature 303, contact 302, wire 3|5 through closedselector contact 3, wire 3, to selector switch relay ||4 and to ground.Thus, in the fourth position, closed selector contacts 2 and 3 providepaths permitting the selector to be advanced into its i'th position ifeither #1 street memory relay set 80 or pedestrian relay 262 isenergized. If neither of these two relays is energized, the' selectorswitch will remain in its fourth position, allowing streets #2 and #a tomaintain the right of way by virtue ci' green lights G2 and G4 and redlights R-l and R-3. The circuit for green lights G--2 and G--4 istraceable from AC at pigtail |64 of relay |50, wire 60|, wire |93,closed selector contact i8, wire |94, terminal |95 where the circuitdivides, one branch passing through bridged contacts |81 to green lightG-2 and to ground; the other branch passing through bridged contacts 200to green light G-4 and to ground. 'I'he circuit for red lights R-I andR3 is traceable from AC at pigtail |64 of relay |50, the closed backcontacts, wire 60|, wire |93, closed selector contacts I9, wire |92,terminal |90, wire ISI, to red lights R-l and R-3 and to ground.`

SELECTOR SWITCH Fmi-H PosrrroN In this position, the parallel amberlight relays |23 and |22 are operated. The circuit for their operationis traceable from AC at pigtail |64 of relay |50, wire 60|, wire |93,closed selector Contact |6, wire 249, to the windings of relays of |22and |23 and to ground. 'I'he holding circuit for these relays istraceable from AC at pigtail |20 of relay |22, contact |26', wire 250,closed cam contacts 25| on amber interval timing motor |56, wire 252,and baci; through the interval, to be described below.`

relay windings to ground. The back contacts |26 and |21 of these relaysopen, deenergizing cams 2| to 21 inclusive. A circuit is traceable fromAC at pigtail 2| of relay |23 through the upper front contact 62| ofrelay 23, wire 255, terminal 256, wire 251, through closed contacts 258and 259 of relays 424 and 451, to amber lights A--2 and A-4respectively,and to ground, thus displaying warning signals to trafc onstreets #2 and #4. A circuit is also traceable from AC at pigtail |2| ofrelay |23, contact |86 oi' relay |23, wire |89, terminal |30,.wire |9l,to red lights R-I and Rf-3 and to ground. Thus, relay |23 maintainsamber lights on #2 and #4 streets and red lights on #1 and #3 streets. Acircuit is traceable from AC at pigtail |20 of relay |22, contact |26',wire 250, to the lower winding of amber interval timing motor |56,energizing this motor. From this point on, the operation of the systemis similar to that described for the second position of the selectorswitch, the contacts |86 closing momentarily to advance the selectorswitch to position #6 shortly before contacts 25| open to deenergize theparallel relays |22 and |23. When the relays are released, upon theirdeenergization, a circuit is traceable from AC, through their closedcontacts |26 and |21, and wire |29 to cam contacts |81, thus continuingthe travel of the motor by energization of its upper winding along wires|51 and |59 until the shaft has where contacts |54 and 25| will be intheir initial position, at which point cam contacts |81 will open. Uponthe release of relays 23 and |22, control of the lights is restored tothe selector switch. As will be explained below, the switch may advancepast the sixth and seventh positions during the interval between theclosure of contacts |86 and the release of relays |22 and |23 by theopening of contacts 25| so that at the instant relays 23 and 22 release,they will transfer the lights either to the condition established in thesixth selector switch position or the condition established in theeighth selector switch position. 'I'he advancement of the selectorswitch to its sixth position is accomplished in the same manner asdescribed for advancement from the second position to the third positionupon closure of contacts |86 and the circuit being completed throughclosed selector contacts 1.

SELECTOR SWITCH SIXTH PosrrroN In this position of the selector switch,the timing mechanism for timing the pedestrian interval is in operation,and red are displayed to all four streets, 1 to 4, inclusive. Thecombination of red and amber displayed simultaneously to each street isone of many possible conventional signals that may be utilized toindicate the right of way to pedestrians and to halt vehicular traffic,as may be readily understood. It would be a simple Inatter to controlany desired form of pedestrian signal, since a separate and distinctselector switch position is provided to control the right of wayindication to pedestrians. The operation of the various parts of thesystem will be described in greater. detail below in the portion of thespecification describing the pedestrian control.

The method by which the selector switch is.

advanced from its sixth position to its seventh position will also bedescribed in discussing the pedestrian control.

advanced to a point and amber lights SELEoToB SWITCH SEVENTH POSITION Inthis position of the selector switch, no amber lights are displayed butall four red lights R-|, R-2, R-3 and R-4 are lighted to keep vehiculartraic stopped while pedestrians who are still traversing the street, andto afford pedestrians an opportunity to reach the opposite side of eachstreet after the red and amber pedestrians' indication has beenextinguished. In the seventh position of the selector switch, lightsRf-I and R--3 are lighted by closed selector contact I9 and lights Rf-2and Rf4 are lighted by closed selector contacts 22. The holding circuitsfor all three memory relays are maintained closed by selector contacts8, 9, and I0. A circuit to the all-red interval timing motor istraceable from AC at pigtail |20 of relay |22, which will be releasedduring the val, closed back contacts |26, wire |28, wire |29, closedselector contact 26, wire 336, wire 338, to magnet 339 and ground and tothe upper winding of the pedestrian and all-red timing motor 3|4 andground. Thus, timing motor 3|4 will rotate wheel 326, causing pin 336'to advance toothed wheel 343 which will be held in its advanced positionby attracted ratchet pawl 342. No initial period mechanism is providedfor shaft 344 of the al1-red timing mechanism, a single adjustment leverbeing sufficient. The all-red interval is of fixed duration and noinitial and maximum intervals are involved. As

soon as wheel 343 has been advanced by pin 326 successively to aposition where contacts 346 close, AC will be supplied through contacts'346, wire 848, and when cam 33| reaches the position where its camfollower permits contacts 330 to close, AC just traced to these contactswill ow through wire 334, wire 22], selector switch relay ||4 and toground which will advance the selector switch to its eighth position.

SELECTOR SWITCH EIGHTH POSITION In the eighth position of the selectorswitch, right of way is restored to streets 1 and 3 and the initial andmaximum intervals are timed. In the eighth position, lights R2 and Rf-4are energized through closed selector contacts 22 and lights G-I and G-3are lighted through closed selector contacts 23. The holding circuits of#29 memory relay and pedestrian memory relay are held by closed selectorcontacts 8 and |0 respectively. A circuit is traceable to the upperwinding of timing motor 202 from AC at pigtail |20 of relay |22, closedback contacts |26, wire |28, terminal |41, wire |29, closed selectorcontacts 24, and wire 350, Where it energizes ratchet magnet 35|,attracting its pawl and armature 352, preparing it to hold toothed wheel353 in an advanced position. AC, just traced to wire 350, also energizesthe upper winding of timing motor 202, one side of which is grounded.This causes shaft 2|8 to rotate, turning wheel 2|1, and advancingtoothed wheel 253 one notch for each revolution of the shaft 2|8. Assoon as the initial interval has expired, as determined by the settingof cam 354 on its shaft in a manner similar to that described above, forstreets #2 and #4, contacts 355 will close. If #l street memory relay#remains deenergized at the instant when cam contacts 224 close, towardthe end of the revolution of shaft 2|8, a circuit will be traceable fromAC at pigtail 84 of memory relay 80, closed back contacts 86, wire 356,closed selector contacts wire 351 to contacts 355, through contacts 224momentarily closed, wire all-red intere 226, wire 221, through selectorrelay. magnet ||4, to ground, advancing the selector switch to the firstposition. In the eighth position, a holding circuit for #l vstreetmemory relay 80 is maintained from AC at pigtail 84 of relay 80, lowercontact 85, wire 9|, closed contacts 90 controlled by cam 89, terminal14, wire 16, terminal 11, and wire 18, to coil 19 of #l street memoryrelay 80. Thus, the alternate shunt holding circuit, including selectorcontacts 9, is opened in the eighth position. Consequently, whencontacts open at the beginning of the revolution of timing motor shaft2|8, #l street memory relay 80 will release. If it is reacted, duringthe last revolution of the initial interval after contacts 90 haveopened and before contacts 224 have closed, the circuit to the selectormotor, through wire 351, closed cam contact and wire 356, will be brokenby the opening of back contacts 86 of relay 19 so that AC will not beapplied to selector relay magnet ||4 upon the closure of contacts 224and an additional revolution of shaft 2|8 will be obtained, thusextending the duration of right of way on streets #l and #3, accorded bygreen lights G-I and G-3. Extension intervals can thus be obtained for#l and #3 streets by successive operations of #1 street memory relay 80in a manner exactly similar to that described above for #2 street memoryrelay |00, and when maximum period contacts 359 are closed by operationof cam 358, the next following closure of contacts 224 will permit AC toow through closed contacts 359, closed contacts 355, cam contacts 224,wire 226, and wire 221 to selector relay magnet I4, and to ground,advancing the selector switch to its first position. This last describedoperation will take place irrespective of whether contacts 86 on #lstreet memory relay 80 are open or closed since AC now arrives atcontacts 355 directly from contacts 359. The selector switch positionone has previously been described.

PEDEsTBIAN CONTROL Located on each of four corners of the intersectionis a pedestrian detector 300, consisting of a push button, treadle, or,if desired, a device operable by body capacity or a photoelectric devicemay be substituted therefor. These four pedestrian detectors 300 areconnected in series to detector relay 30| which is exactly similar inall respects to #1 street detector relay 56 and which is therefore notillustrated in detail, Operation of any one of the four seriallyconnected pedestrian detectors 300 will open the circuit of detectorrelay 30| and close a circuit traceable from AC through the relayarmature, shown dotted, wire 248, Iterminal 308, terminal 309, to thewinding of pedestrian memory relay 262, and ground. Assuming that theselector switch 65 is in its first position and that there is no callfor the signal by either street #2 or street #4, #2 street memory relay|00 will be released and its back contacts |04 will be closed. A circuitis traceable to selector switch relay ||4 from AC at pigtail 260 ofpedestrian memory relay 262, contacts 302,l

minal |49 to the parallel windings ofrelays 50 and 'I'hese relaysthereupon close their iront contacts.

rI'he selector switch, is advanced from its second to its third positionby a circuit traceable from AC at pigtail |06, closed back contacts |04of #2 street memory relay 80, wire 22|, wire 620, selector contacts 5which are closed in the second position, and wire I3, to selector relay||4 and to ground, advancing switch to its third position.

The relays |50 and |5| just referred to have closed their front contactsand a circuit is traceable from the upper contact |62 of relay |50, wire|66, closed contacts |69 of amber interval timing motor, wire toselector contacts 4 which are closed in the third position of theselector switch, wire ||3, selector relay I4 and ground, advancing theselector from its third to its fourth position.

In the fourth position of the selector switch, a circuit is traceable toadvance the switch to its fth position, from contacts 302 of pedestrianmemory relay 262, beginning with `AC at pigtail 260, armature 303,contacts 302, Wire 3|5, selector contacts 3 which are closed in thefourth position, and wire ||3 to selector switch relay l I4, advancingthe selector switch from its fourth to its fth position.

In the fth position of the selector switch selector contacts 1 areclosed and the switch is advanced from the fifth to the sixth positionby a circuit traceable from AC at pigtail |64 of relay 115i), armature|63, the upper contact |62 of relay |50, wire |66, cam contacts |86which close before the cam contacts |54 open, releasing the amber lightrelays |50 and |5|, wire |61, selector contacts 1 closed in the fthposition, wire H3, and relay ||4. This carries the switch from the iifthinto the sixth position where the selector switch is prepared to givethe pedestrian indi cation upon the release of relays |50 and |5l.Before contacts |69 reclose, contacts |54 open releasing amber lightrelays |50 and |5| and deenergizing the cam follower of `cam |68 so thatit will not advance the selector switch through the sixth positionalthough selector contact 4 is closed in the sixth position.

In the sixth position of the selector switch, lights A| and A-3 andlights Rte-2 and Rf-4 are lighted during the operation of amber lightmotor l56 by the front contacts |13 of amber light relay I5|. In thesixth position of the selector switch, these lights are also lighted byclosed selector contacts 2| and 22 and upon the release of amber lightrelays |50 and |5| they remain lighted. In addition, the release ofrelay i150 closes a circuit traceable from AC at pigtail |60 of relay|50, its closed back contacts, wire 60|, wire |93, selector contacts |9and 20, to red lights Rf-| and R-3 and amber lights A-2 and A-fllrespectively, and since both selector contacts i9 and 20 are closed inthe sixth position, immediately upon the release of relay |50 amberlights A--I and A-S and red lights R--I and R-3 will be lighted by thecircuit just traced. This results in the display of red and amber on allfour streets, giving a distinctive signal to pedestrians as previouslydescribed. The timing of the pedestrian period is accomplished asfollows: the lower portion of the timing motor 3|4 is similar in allrespects to the timing motor 202 used for the G-2 and G-4 lights andpreviously described, comprising an initial interval cam 324, a maximuminterval cam 325. Corresponding adjusting levers for these cams aresimilar to those provided in timing motor 202. A circuit is traceablefrom pigtail |20 of relay |22, back contacts |26, wire |28, terminal|41, wire |29 to closed selector contacts 25, wire 3|6, terminal 3|1,and wire 3|8 to the lower winding of timing motor 3|4, which accordinglybegins to revolve. A circuit is also traceable from terminal3|1 to pawlmagnet 3|9 which prepares to hold toothed wheel 322 in an advancedposition. After the completion of the predetermined number ofrevolutions for the initial interval of the pedestrian period, contacts328 are closed by the action of cam 324, and if the pedestrian memoryrelay 262 should not be operated by further pedestrian traflic, it willrelease and a circuit will be traceable from AC at pigtail 260 of relay262, closed back contacts 26|, wire 263, wire 332, closed selectorcontacts I3, wire 333 to contacts 328 and immediately upon the closureof contacts 330 at the end of the final revolution of the initialinterval, contacts 330 will close, permitting AC just traced to thesecontacts to low through wire 334 and wire 221 to selector relay ||4,which will thereupon become energized and will advance the selectorswitch into the seventh, or all-red position. Y

The timing operations in this all-red position have been previouslydescribed and need not be described again.

As in the case of memory relays 80 and |00, two holding circuits aretraceable for pedestrian memory relay 262. One of these is traceablefrom AC at pigtail 260 of relay 262, armature 303, contacts 302',terminal 305, wire 306, the selector contacts I0 which are open only inthe sixth position of the selector switch during the timing of thepedestrian interval, wire 301,'terminal 308, terminal 309, to thewinding of relay 262 and ground. Thus, at all times except in theselector switch position, pedestrian memory relay 262 will have a closedholding circuit including selector contact |0. During the pedestriantiming interval, however, the selector contact is open and the circuitis then traceable from AC at pigtail 360, contact 302', terminal 305,wire 3|I, contacts 3|2 controlled by cam 3|3, wire 3|0, terminal 309 andthe winding of relay 262 to ground. Thus, during the timing of thepedestrian interval, pedestrian memory relay 262 is subject to thecontrol of cam contacts 3|2. Contacts 3|2 open momentarily during theearly portion of each revolution of the pedestrian motor 3|4 andpedestrian relay 262 will then be released. If it is reoperated duringthe final revolution of the initial period, contacts 328 will bedeenergized by opening of the back contacts 26| of relay 262 and theselector switch will not ad- Vance upon closure of cam contacts `330. Anadditional revolution of the timing order will result, giving anextension period for the pedestrian traflic. During each extensionperiod an additional period may be obtained, but this succession ofadditional periods cannot go beyond the maximum which is determined byclosure of cam contacts 329. When cam contacts 329 close, a path from ACis traceable through contacts 329, contacts 328 already closed, andcontacts 330 which close at the end of the timing motor revolution. Thisadvances the selector switch regardless of the position of memory relay262. If pedestrian memory relay 262 should 'be operated, however, theholding circuit including selector contact I0 will keep it operateduntil the selector switch again comes around to position 6 and timingmotor 3 I4 makes another revolution. Thus, a call by a pedestrian duringthe last timing revolution of the maximum period will be retained andwill aflord the pedestrian a new interval in the next signal cycle inwhich to traverse the intersection.

At the beginning of the description oi' the pedestrian control it wasassumed that #2 street memory relay was not operated and that its backcontacts |04 were closed. Consequently, circuits were traceable to theselector switch magnet ||4 in each or the successive positions from theiirst position of the selector switch up to the sixth position, which isthe pedestrian interval timing position. These successive steps are allaccomplished within the duration of the amber interval for streets #land #3. Ii #2 street memory relay |00 had been operated by actuation ofa vehicle. its back contacts |04 would have been opened and it would nothave been possible to trace a circuit from AC along wires 22| and 620and through selector contact 5 which is closed only in the secondposition. It will be observed that one of the contacts from to 6inclusive are qlosed in the second position except selector contact 5and consequently the switch cannot advance into its third position untilcontacts |86 close toward the latter portion of the revolution of theamber interval timing motor. When contacts l|86 close, contacts |69 openand although selector switch 65 has advanced to its third position, itwill not skip through this position because contacts |69 do not recloseuntil after contacts |54 have opened and released the amber light relayswhich supply AC to contacts |86 and |69. This succession of operationsall takes place within the amber light interval for streets #l and #3and brings the selector switch 65 into its correct position to displaythe pedestrian amber and red indications before relays |50 and |5|release.

Similarly, if there is no pedestrian actuation the following descriptionwill illustrate how it is possible for the selector switch to skip fromits rest position with G-2 and G-4 lights lighted, to its eighthposition which transfers right of way to streets #l and #3, thusavoiding the necessity for holding up trafc when no pedestrians wish tocross the intersections. This operation is accomplished in the followingmanner: starting from the fourth position of the selector switch withlights G--2 and G-4 and lights Rf-I and R-3 lighted, assume that avehicle from street #l energizes memory relay 60 as previouslydescribed. A circuit is traceable from AC at upper contact 85 of memoryrelay 80, wire 93, selector contact 2 which is closed in the fourthposition, and wire I3 to selector relay ||4 which is thereupon energizedand causes the selector switch to advance from the fourth to the fthposition.

In the fifth position, a circuit is traceable from AC at pigtail 260 ofpedestrian memory relay 262, which we have assumed to be deenergized,through closed back contacts 26|, wire 263, to selector switch contact6, which is closed in the fifth position, and along wire ||5 to selectorswitch relay ||4 which thereupon operates and advances the selectorswitch from its fifth into its sixth position.

In the fifth position, selector contacts I6 were closed, which energizedamber light relays |22 and |23 by a path which may be traced from AC atpigtail |64 of relay |50, its closed back contacts,

wire 60|, wire |93, closed selector contact |6, which is closed only inthe fifth position, and wire 249 to windings of amber light relays |22and |23 for streets #2 and #4.

As previously described, the upper front contacts of relay |23 supply ACto amber lights A`2 and A--4, and the lower contacts to lights Rf-l andRf-3. The upper contact of relay |22 provides a circuit to advance theselector switch from the sixth into the seventh position, which istraceable from AC at plgtail |20 of relay |22,

wire |66, to closed cam contacts |69, which are closed through the earlyportion of the timing interval of amber light motor |66, wire |10, toselector contacts 4 which are closed in the sixth selector position andalong wire I|3 to selector relay I4 which advances the selector switchfrom its sixth into its seventh position.

Toward the end of the amber interval, contacts |86 close, permitting AC,just traced to wire |66, to pass now through contacts |86 instead of |69and along wire |81 to selector contacts 1, which are closed in theseventh position, wire I3 and selector switch relay ||4, thereuponadvancing selector switch 65 from its seventh into its eighth position.The eighth position, as will be recalled, is the position of theselector switch for timing the duration of right of way for streets #land #3, and becomes eiective immediately upon the release of amber lightrelays |22 and |23, as previously described.

Three switches, 310, 31|, and 313, are provided, each of which serves toenergize permanently one of the three memory relays previouslydescribed. Closure of switch 310 will connect AC to wire 91, wire 99, #2street memory relay |00, holding this relay permanently energized sothat it cannot be released. In this condition, irrespective ofactuations by pedestrians or trailic on #l street, the right of way willalways return to #2 street and remain there for the maximum periodbefore it may be obtained by either pedestrians or #l street.

Similarly, closure of switch 31| will apply AC to wire 13, wire 16,terminal 11, wire 18, to the winding of #l street memory relay 80.Correspondingly, switch 313 will supply AC to wire 248, terminal 309 andthe winding of pedestrian memory relay 262. When any one of these relaysis thus permanently energized: its corresponding maximum time intervalwill be included in each signal cycle and the signal mechanism willalways accord right of way permanently to the street having theenergized memory relay in the absence of actuations by vehicles orpedestrians on either of the other two relays remaining deenergized.

If two such relays are simultaneously permanently energized by closureof these switches, the signal will alternately accord right of way iirstto one street and then to the other. It should be noted that noprovision is made for skipping the eighth position of the selectorswitch and thus omitting the minimum interval of right of way to streets#l and #3. It is contemplated that lights and 3 will be displayed to themore heavily traveled of the two intersecting thoroughfares. It will benoted that if there is no trailic on either #l or #3 street andpedestrian relay 262 is permanently energized by closing switch 313, themechanism will accord the maximum pedestrian interval followed by atleast the minimum traflic interval for streets #l and #3, it beingimpossible for the mechanism to skip through the right of Way intervalfor streets #l and #3. The right of way interval for streets #2 and #4,however, will be omitted in the event that there is no actuation ofrelay |00 by traffic on either of these streets. Thus, i1 any detectorcircuit is disabled by the breaklng thereof, it will have the sameeffect as permanently closing one of the switches 310, 31|, or 313, andthe worst possible effect is to accord the maximum interval of right ofway in each signal cycle to the street having the disabled detector.

If all three switches, 310, 31|, and 313, are closed simultaneously, themechanism will automatically first accord the maximum interval of rightof way to #l street, then to #2 street, and then to the pedestrianinterval, these periods following each other in rotation. This would bethe result obtained if all three detector circuits were simultaneouslybroken. It will also be noted in the case of conflicting calls on thevarious streets and the pedestrian detectors, that the memory relayholding circuits are opened by selector switch 65 only during the timinginterval-for each particular street, so that the memory relays willremain energized until these timing intervals permit them to be reset,and the signal cycle will successively proceed to each right of wayinterval in rotation.

In the case of conflicting calls where one street is already in itstiming interval, extensions will be granted to the street whose timinginterval is in progress, until the maximum period has expired.

VEHICULAB SPEED CONTROL Each of the streets leading to the intersection,or one or more of them, may be provided with devices arranged to displayautomatically a red light to the street upon which vehicle approaches.These devices may be mechanical or electrical and of any convenient formwhich will respond to the passage of a vehicle, although they areillustrated diagrammatically in the drawing of Fig. 3 as of themechanical type for purposes of simplicity in illustration.

The speed detectors comprise two spaced depressable bars, plates, or thelike, arranged across the traffic lane and responsive to vehiclesapproaching the intersection. For example, in #l street, these detectorsare designated 40 and 4l; in #3 street, they are designated 40 and 4|;in #2 street, they are designated 400 and 4|0; and in #4 street, theyare designated 400 and 4|0. The detector plates or bars may be veryclosely placed to each other and to corresponding traine regulatingdetectors 50 and 50', 500 and 500'. If desired, all three detectors maybe enclosed in any convenient form of common housing which is adapted tobe inserted in street. The circuits in the arrangement of the speeddetecting devices are illustrated for #l and #3 streets and it will beunderstood that the arrangements of circuits for the speed detectors for#2 and #4 streets are the same. The leading detector 40, which isengaged by the front wheel of a Vehicle approaching the intersecton, isarranged to bridge contacts 40|, the left contact being connected to ACand the right contact being connected by wire 405 to one of the contacts406 of the second detector 4|; the other contact 401 is connected bywire 408 to the coil of relay 409; the other side of the relay coilbeing grounded.

The second detector 4| is provided with a sec- 4ation of the period ondarmature 42, arranged to bridge contacts 4|3 in the circuit of holdingmagnet 4|4 of the first speed detector 40. Each of the speed detectors,40 and 4|, is provided with' a dash pot which, when actuated, holds thecorresponding armature inengagement with its contacts for apredetermined period of time, the dash pot for the first speed detector40 being designated 4|5; the dash pot for'the second speed detectorbeing designated 4|6. These dash pots may be of conventional design andare adjustable by means of valves 4I1 so that their periods of closuremay be adjusted at will.

The relay 409 is provided with three armatures, |80, |40, and 4|8.Armature |80 is normally engaged with contacts |19 in the circuit of #lstreet amber light A-|. Armature |40 normally bridges contacts |39 inthe circuit of #l street green light G|, while armature 4|8 isdisengaged from contacts 4|9 which lie in a normally open circuit fromAC to #l street red light R-I.

The dash pot 4|5 of the first detector contact 40 is adjusted by itsvalve 4|1, so that when the front wheels of a vehicle engage detector40, the closed contacts 40| will open before the front wheels of avehicle engage the second detector 4|, provided that the vehicle istraveling at a speed less than the maximum permissible rate. If thevehicle is exceeding the predetermined maximum speed limit, such as whenan operator observes the amber light and attempts to speed across theintersection before the signal is changed to red, leading speed detector40 Will still be closed when the front Wheels of the vehicle engage thesecond speed detector 4| to bridge contacts 401 and 406. The circuitsestablished thus provide a path traceable from AC at contacts 40|, coil4|4 of detector 40, contact 4 I3 of detector 4 I, to ground at contact4|3, thus holding contacts 40| closed. From contacts 40|, a path istraceable from AC through contacts 40 I,

v wire 405, contact 406, through closed detector 4|,

Whose dash pot has not yet permitted its contacts to open, conrtact 401,and Wire 408 to the coil of relay 409 and to ground, thus energizingrelay 409 and breaking the 'circuit of green light G-| at contact I 39,and the circuit of amber light A--I at contact |19, and closing acircuit from AC through contact 4|9 to red light R-L Thus, if amberlight A-l or green light G-l is lighted, it will be immediately changedto red. The durof illumination of the #1 street red light R-I ispredetermined by the adjustment of valve 4|1 of dash pot 4|6 of thesecond speed detector 4| and when the contacts of this detectordisengage, detector 40 is permitted to restore to normal and open thecontacts 406 and 401; the circuit of the winding of relay 409 is openedand this relay then releases restoring lights R-I, A--I and Gl-I totheir normal control by the timing mechanism. Speed detectors 40 and 4|'are similarly arranged as are the detectors 400', 4I0, 400 and 4|0 sothat description of the operation of these detectors is not necessary.

While this speed detector system is preferably associated with a maintrafc regulating system to appropriate the control of the street onwhich the speeding vehicle is traveling, from the main signal system,nevertheless, this speed arrangement may be arranged separately toextinguish a normal clear" signal such as a green light, and illuminatea red light or other stop signal in the manner described. Also, incertain instances, it may be advisable simply to employ no clear signalwhatever but simply a normally extinguished red light, which is ashedagainst the speeding vehicle if it exceeds the predetermined speed limitin the manner described.

It will be seen that the new traffic regulating system automaticallyadapts itself to the volume and nature of the traffic negotiating theintersection at which it is located. Furthermore, the new system isselectively adjustable to provide the exact type of traic control whichthe local requirements may dictate. Thus, the new system may be mountedat any intersection and easily adjusted at any time to conform totrafllc requirements.

I claim:

1. In a traiiic regulating system providing signal control forpermitting pedestrian traflic to traverse a vehicular trafc lane, atralc signal for said vehicular traic lane, to provide a stop and "gosignal therefor, switching means for energizing said tralic signal,control mechanism for actuating said switching means, and traflicactuable means responsive to pedestrian trafic desirous of negotiatingthe'vehicular traffic lane for appropriating the control of the trafcsignal to energize the stop signal controlling the flow of trame in thevehicular traic lane to accord ped estrians the right of way.

2. In a traffic regulating system providing signal control forpermitting pedestrian trafc to traverse a vehicular traffic lane, atraic signal for said vehicular traffic and pedestrian trailic lanes, toprovide a stop and go signals therefor, switching means for energizingsaid traiilc signal, control mechanism for actuating said switchingmeans, and traic actuable means responsive to pedestrian traflicdesirous of negotiating the vehicular trahie lane for appropriating thecontrol of the traffic signal to energize the stop signal controllingthe flow of traffic in the vehicular traffic lane and energize a gosignal for the pedestrian trac lane.

3. In a traic regulating system for an intersection of at least twostreets, the combination of signal devices, mechanism for operatingthem, means responsive to traiiic connected to said mechanism forinitiating operation of said devices to signal the right of way on atleast one street to said trailc, means for operating said devices tomaintain the right of way on said one street for a predetermined periodof time, means for extending the period of operation of said signaldevices to maintain the right of way on said one street for .additionalpredetermined periods of time, each of which is measured from theexpiration of the preceding period, said period extending means beingoperable to provide an additional right of way period on said one streetin response to actuation by following traiilc on said one street onlyduring a time interval occurring near the end of the preceding period,and means for adjusting said period extending means to vary the numberof permissible additional periods.

4. In a traflic regulating system for an intersection of at least twostreets, the combination of signal devices, mechanism for operatingthem, means responsive to traffic connected to said mechanism forinitiating operation of said devices to vsignal the right of way on atleast one street to said trafc, means for operating said devices tomaintain the right of way on said one street for a predetermined periodof time, means for extending the period of operation of said signaldevices to maintain the right of way on said one street for additionalpredetermined periods of time, each of which is measured from theexpiration of the preceding period, said period extending means beingoperable to provide an additional right of way period on said one streetin response to actuation by following traffic on said one street onlyduring a time interval occurring near 4the end of the preceding period,means for adjusting said second means to vary the initial period ofoperation of said signal devices, and means for adjusting said periodextending means to vary the number of permissible additional periods.

5. In a traic regulating system for an intersection oi' at least twostreets, the combination of signal devices including a stop signal foreach street. vehicular traiiio responsive means controlling theenergization of the devices to accord the right of Way to vehiculartraffic on the respective streets in response to the approach ofvehicles on such streets, and means responsive to pedestrian trafficseeking to negotiate at least one of the streets of the intersection forappropriating the control of said signal devices to energize the stopsignal devices for all streets.

6. In a traflic regulating system for an intersection of at least twostreets, the combination of signal devices including a stop signal foreach street, vehiclar trailc responsive means controlling theenergization of the devices to accord the right of way to vehiculartraffic on the respective streets in response to the approach ofvehicles on such streets, means responsive to pedestrian traic seekingto negotiate at least one of the streets of the intersection forappropriating the control of said signal devices to energize the stopsignal devices for all streets, andmeans for rendering said pedestriantralc responsive means unresponsive to pedestrian traflic for apredetermined period of time.

7. In a traflic regulating system for an intersection of at least twostreets, the combination of signal devices including a stop signal foreach street, vehicular traiilc responsive means controlling theenergization of the devices to accord the right of way to vehiculartramo on the respective streets in response to the approach of vehicleson such streets, means responsive to pedestrian traic seeking tonegotiate at least one of the streets of the intersection forappropriating the control of said signal devices to energize the stopsignal devices for all streets, and mechanism actuated by saidpedestrian trafc responsive means for maintaining said stop devicesenergized for a predetermined period of time.

8. In a traiiic regulating system for an intersection of at least twostreets, the combination of signal devices including a stop signal foreach street, means controlling the energization of the devices in thealternative to provide the right of way to vehicular trafllc on thestreets, means responsive to pedestrian traflic seeking to negotiate atleast one of the streets of the intersection for appropriating thecontrol of said means to energize the stop signal devices for allstreets, and mechanism responsive to successive actuation of said meansby following pedestrian traffic for extending the period of operation ofsaid stop signals a predetermined period of time. i

PAUL P. HORNI.

